NGC 381

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NGC 381
NGC 381 PanS.jpg
Observation data (J2000 epoch)
Right ascension 01h 08m 19.9s [1]
Declination +61° 35′ 02″ [1]
Distance 3,120 ± 300  ly (957 ± 93  pc) [2]
Apparent magnitude  (V)9.3 [3]
Apparent dimensions (V)6′ [1] or 7′ [3]
Physical characteristics
Mass32.4+45.2
−18.9 [4]   M☉
Radius15 ly [5]
Estimated age316+39
−34 [2]
Other designations Collinder 10 [6]
Associations
Constellation Cassiopeia [3]
See also: Open cluster, List of open clusters

NGC 381 is an open cluster of stars in the northern constellation of Cassiopeia, located at a distance of approximately 3,120 light-years from the Sun. [2] Credit for the discovery of this cluster was given to Caroline Herschel by her brother William in 1787, although she may never have actually seen it. [7]

This is a Trumpler class III 1 m cluster of intermediate age, [1] estimated at 316 million years. This class indicates the cluster is relatively weakly concentrated, with a small brightness range and an intermediate richness of stars. A total of 350 probable members have been identified, down to 20th magnitude, [2] and the cluster contains about 32 times the mass of the Sun. [4] The cluster has a core angular radius of 2.99′±0.93′ and an outer cluster radius of 5.6′±0.1′. [2] It has a physical tidal radius of 15 ly (4.7 pc). [5] No giant stars have been discovered in this cluster. [1] Four candidate variable stars have been found in the field of NGC 381; one of which is a suspected cluster member. [8] The eclipsing binary OX Cassiopeiae was once thought to be a member, but is now known to be a background star system. [9]

Related Research Articles

<span class="mw-page-title-main">Cassiopeia (constellation)</span> Constellation in the northern celestial hemisphere

Cassiopeia is a constellation and asterism in the northern sky named after the vain queen Cassiopeia, mother of Andromeda, in Greek mythology, who boasted about her unrivaled beauty. Cassiopeia was one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive 'W' shape, formed by five bright stars.

<span class="mw-page-title-main">Messier 26</span> Open cluster in the constellation Scutum

Messier 26, also known as NGC 6694, is an open cluster of stars in the southern constellation of Scutum. It was discovered by Charles Messier in 1764. This 8th magnitude cluster is a challenge to find in ideal skies with typical binoculars, where it can be, with any modern minimum 3-inch (76 mm) aperture device. It is south-southwest of the open cluster Messier 11 and is 14′ across. About 25 stars are visible in a telescope with a 150–200 mm (6–8 in) aperture.

<span class="mw-page-title-main">Messier 18</span> Open cluster in the constellation Sagittarius

Messier 18 or M18, also designated NGC 6613, is an open cluster of stars in the constellation Sagittarius. It was discovered by Charles Messier in 1764 and included in his list of comet-like objects. From the perspective of Earth, M18 is situated between the Omega Nebula (M17) and the Small Sagittarius Star Cloud (M24).

<span class="mw-page-title-main">Messier 50</span> Open cluster in the constellation Monoceros

Messier 50 or M 50, also known as NGC 2323, is an open cluster of stars in the constellation Monoceros. It was recorded by G. D. Cassini before 1711 and independently discovered by Charles Messier in 1772 while observing Biela's Comet. It is sometimes described as a 'heart-shaped' figure or a blunt arrowhead.

<span class="mw-page-title-main">Messier 93</span> Open cluster in the constellation Puppis

Messier 93 or M93, also known as NGC 2447, is an open cluster in the modestly southern constellation Puppis, the imagined poop deck of the legendary Argo.

<span class="mw-page-title-main">NGC 1502</span> Open cluster in the constellation Camelopardalis

NGC 1502 is a young open cluster of approximately 60 stars in the constellation Camelopardalis, discovered by William Herschel on November 3, 1787. It has a visual magnitude of 6.0 and thus is dimly visible to the naked eye. This cluster is located at a distance of approximately 3,500 light years from the Sun, at the outer edge of the Cam OB1 association of co-moving stars, and is likely part of the Orion Arm. The asterism known as Kemble's Cascade appears to "flow" into NGC 1502, but this is just a chance alignment of stars.

<span class="mw-page-title-main">Phi Cassiopeiae</span> Star in the constellation Cassiopeia

Phi Cassiopeiae is a star in the constellation Cassiopeia. φ Cassiopeiae is a multiple star with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".

<span class="mw-page-title-main">NGC 2506</span> Open cluster in the constellation Monoceros

NGC 2506 is a mildly-elongated open cluster of stars in the equatorial constellation of Monoceros, located at a distance of 12.7 kly from the Sun near the Galactic anti-center. It was discovered by William Herschel in 1791. The cluster lies around 10,000 ly from the Galactic Center and about 1,600 ly above the Galactic plane. It is of intermediate age, estimated at around two billion years. The cluster has an angular radius of 12′ and a core radius of 4.8′.

<span class="mw-page-title-main">HD 36960</span> Star in the constellation Orion

HD 36960 is a B-type main-sequence star in the constellation Orion. At an apparent magnitude of +4.78 it is easily visible to the naked eye in many areas, though in most urban areas it cannot be seen due to light pollution. Although it does not have a Bayer or Flamsteed designation, it is brighter than over 30 Flamsteed stars in Orion, as well as being brighter than any of the stars in the nearby Orion Nebula such as θ1 Orionis C and θ2 Orionis.

<span class="mw-page-title-main">NGC 637</span> Open star cluster in the constellation Cassiopeia

NGC 637 is an open cluster of stars in the northern constellation of Cassiopeia, positioned about 1.5° to the WNW of the star Epsilon Cassiopeiae. The cluster was discovered on 9 November 1787 by German-born English astronomer William Herschel. It is located in the Perseus Arm of the Milky Way, at a distance of approximately 7.045 kilolight-years from the Sun. The cluster is small but compact, and is readily visible in a small telescope.

<span class="mw-page-title-main">NGC 2439</span> Open cluster in the constellation Puppis

NGC 2439 is a sparse open cluster of stars in the constellation Puppis. It has an apparent visual magnitude of 6.9, an angular size of 10 arcminutes, and is visible using a small telescope. This is a young cluster with age estimates in the range of 20–300 million years. It has a tidal radius of approximately 82 light years. No chemically peculiar stars have been found.

<span class="mw-page-title-main">NGC 433</span> Open cluster in the constellation Cassiopeia

NGC 433 is an open cluster in the northern constellation of Cassiopeia, located at a distance of 6,500 light years from the Sun. It was discovered on September 29, 1829 by John Herschel, and was described by John Dreyer as "cluster, small, a little compressed." The cluster is considered on the poor side, with only 12 stars above magnitude 16. It has a linear diameter of 26.3 ly, with around 479 times the mass of the Sun and an age of 65 million years.

<span class="mw-page-title-main">NGC 7209</span> Open cluster in the constellation Lacerta

NGC 7209 is an open cluster in the constellation Lacerta. It was discovered by William Herschel on 19 October 1787. The cluster lies 3,810 light years away from Earth. It has been suggested that there is another cluster at a distance of 2,100 light years projected in front of a cluster lying at 3,800 light years away, based on the reddening of the cluster, however, further photometric studies of the cluster did not support that claim.

<span class="mw-page-title-main">NGC 2539</span> Open cluster in the constellation Puppis

NGC 2539 is an open cluster in the constellation Puppis, located at the north edge of the constellation. It was discovered by William Herschel on January 31, 1785. It is a moderately rich cluster and with little central concentration, with Trumpler class II1m.

<span class="mw-page-title-main">NGC 5460</span> Open cluster in the constellation Centaurus

NGC 5460 is an open cluster in the constellation Centaurus. It is a bright but loose cluster of intermediate age located approximately 2,300 light years away from Earth. It is located nearly 2 degrees east-southeast of Zeta Centauri.

<span class="mw-page-title-main">NGC 5617</span> Open cluster in the constellation Centaurus

NGC 5617 is an open cluster in the constellation Centaurus. NGC 5617 forms a binary open cluster with Trumpler 22. It lies one degree west-northwest of Alpha Centauri.

<span class="mw-page-title-main">NGC 5316</span> Open cluster in the constellation Centaurus

NGC 5316 is an open cluster in the constellation Centaurus. It was discovered by James Dunlop in 1826. Located approximately 4,000 light years away from Earth, it is located in the Carina-Sagittarius arm.

<span class="mw-page-title-main">NGC 4103</span> Open cluster in the constellation Crux

NGC 4103 is an open cluster in the constellation Crux. It was discovered by James Dunlop in 1826. It is located approximately 5,000 light years away from Earth, in the Carina-Sagittarius arm.

NGC 4815 is an open cluster in the constellation Musca. It was discovered by John Herschel in 1834. It is located approximately 10,000 light years away from Earth.

References

  1. 1 2 3 4 5 Ann, H. B.; et al. (February 2002). "BOAO Photometric Survey of Galactic Open Clusters. II. Physical Parameters of 12 Open Clusters". The Astronomical Journal. 123 (2): 905–914. arXiv: astro-ph/0203028 . Bibcode:2002AJ....123..905A. doi:10.1086/338309. S2CID   15064411.
  2. 1 2 3 4 5 Maurya, Jayanand; Joshi, Yogesh Chandra (October 2018). "Photometric study of the open cluster NGC 381". Bulletin de la Société Royale des Sciences de Liège. 88: 291–294. doi: 10.25518/0037-9565.9003 .
  3. 1 2 3 Finlay, Warren H. (2014). Concise Catalog of Deep-Sky Objects. The Patrick Moore Practical Astronomy Series (Second ed.). Springer. p. 155. doi:10.1007/978-3-319-03170-5. ISBN   978-3-319-03169-9.
  4. 1 2 Joshi, Y. C.; et al. (October 2016). "Study of open clusters within 1.8 kpc and understanding the Galactic structure". Astronomy & Astrophysics. 593: 13. arXiv: 1606.06425 . Bibcode:2016A&A...593A.116J. doi:10.1051/0004-6361/201628944. S2CID   118610932. A116.
  5. 1 2 Piskunov, A. E.; et al. (January 2008). "Tidal radii and masses of open clusters". Astronomy and Astrophysics. 477 (1): 165–172. Bibcode:2008A&A...477..165P. doi: 10.1051/0004-6361:20078525 .
  6. ↑ "NGC 381". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 22 December 2006.
  7. ↑ Hoskin, Michael (August 2006). "Caroline Herschel's catalogue of nebulae". Journal for the History of Astronomy. 37 (3): 251–255. Bibcode:2006JHA....37..251H. doi:10.1177/002182860603700301. S2CID   115235207.
  8. ↑ Hu, J. -H.; Ip, W. -H. (August 2007). Search for Exoplanets and Variables in the Open Cluster NGC 381. Binary Stars as Critical Tools and Tests in Contemporary Astrophysics, International Astronomical Union. Symposium no. 240, held 22–25 August 2006 in Prague, Czech Republic, S240. p. 333. Bibcode:2007IAUS..240..333H.
  9. ↑ Crinklaw, Greg; Etzel, Paul B. (October 1989). "A Photometric Analysis of the Eclipsing Binary OX Cassiopeiae". Astronomical Journal. 98: 1418. Bibcode:1989AJ.....98.1418C. doi: 10.1086/115228 .
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